infinitivestem

Infinitivstamm, or infinitive stem, is a term in German grammar describing the base form of a verb obtained by removing its infinitive ending (-en, -n, or -ieren). The infinitivstamm provides the core material for most verb conjugations and related forms, acting as the melodic and morphological foundation for the verb.

Formation and examples

- Regular -en or -n verbs: remove the ending to get the stem. Examples: arbeiten → arbeit-, lernen → lern-, spielen → spiel-.

- -ieren verbs: remove -ieren, yielding a stem that typically ends in -ier-. Examples: studieren → studier-, faszinieren → faszinier- (present forms then attach endings: ich studiere, du studierst, er studiert).

- Verbs with prefixes: the stem is taken from the base verb, with prefixes treated as part of the stem in many conjugations. Examples: aufstehen → steh- (ich stehe, du stehst), verstehen → versteh- (ich verstehe).

- Umlaut and ablaut: for some strong verbs, the stem vowel changes in certain finite forms, producing variants such as fahr- in fahren (du fährst, er fährt), where the infinitivstamm is fahr-, but other forms show umlaut.

Usage

- The infinitivstamm combines with person endings to form the present and other finite tenses (ich arbeite, du arbeitest, er arbeitet) and with modifiers to create participles (ge- + stem + -t or -en, as in gemacht, gesehen).

- It also helps explain irregularities and vowel changes across tense forms, and it serves as a reference point in language teaching and grammar descriptions.

- In Germanic languages the concept has parallels, where a verb’s stem guides conjugation across moods and tenses.

See also: infinitive, conjugation, stem.